Conventionally, a foamer dispenser described in, for example, Patent Document 1 below is known. This foamer dispenser includes: an attachment cap that is attached to a mouth portion of a container main unit in which a content substance is to be contained; a discharge device with a stem that is erected through the attachment cap so as to be movable downwardly while being biased upwardly; and a depressing head which is attached to the stem and in which a nozzle hole is formed.
The discharge device includes: a piston for liquid that is linked to the stem; a cylinder for liquid in which the piston for liquid is contained so as to be freely slidable in the up-down direction; a piston for air that is linked to the stem; and a cylinder for air in which the piston for air is contained so as to be freely slidable in the up-down direction. The discharge device further includes: an air-liquid mixing chamber that mixes liquid from the cylinder for liquid with air from the cylinder for air; and a foaming member that is disposed between the air-liquid mixing chamber and the nozzle hole and foams an air-liquid mixture from the air-liquid mixing chamber.
The attachment cap includes: an annular ceiling wall portion that is arranged above the mouth portion of the container main unit; and a guide cylindrical portion that is erected on an inner circumferential edge of the ceiling wall portion. The depressing head includes: a top wall portion that is arranged above the stem; an attachment cylindrical portion that extends downwardly from the top wall portion and is attached to the stem; and an exterior cylindrical portion that extends downwardly from the top wall portion and surrounds the attachment cylindrical portion and the guide cylindrical portion from the outer side in the radial direction. The inside of the exterior cylindrical portion is in communication with the inside of the cylinder for air through the inside of the guide cylindrical portion.
In the foamer dispenser with this structure, when the depressing head is depressed to move the stem downwardly against the biasing force, the discharge device is activated to cause a foam-like content substance to be discharged from the nozzle hole. After that, when the depressing of the depressing head is released to allow the biasing force to move back the depressing head together with the stem upwardly, the inside of the cylinder for air has a negative pressure. Then, the air is sucked into the exterior cylindrical portion from the outside of the foamer dispenser through a gap between the inner circumferential surface of the exterior cylindrical portion and the outer circumferential surface of the guide cylindrical portion (hereinafter, referred to as “cylinder-cylinder gap”) and is subsequently drawn into the cylinder for air through the inside of the guide cylindrical portion.